Phonograph diaphragm and sound box



May 1, 1923. 1,453,336

c. c. BROSKIE PHONOGRAPH DIAPHRAGM AND SOUND BOX Filed July 21, 1919 anus utoz I I l I Patented May 1, 1923.

\. OFFICE,

FATE

CHARLES CECIL BROSKIE, OF STONE, KENTUCKY.

PHONOGRAPH DIMPHRAGM AND SOUND BOX.

Application filed July 21, 1919. Serial 121 0,. 312,175.

To all whom it may concern:

Be it known that 1, CHARLES CECIL Bnos- KIE, a citizen of the United States, residing at Stone, in the county of Pike and State of Kentucky, have invented a new and useful Phonograph Diaphragm and Sound Box, of which the following is a specification.

The present invention is a phonograph diaphragm and sound box, the principal object being to provide a diaphragm which will obviate the burring sound ordinarily experienced in talking machines; and which renders the sound waves clear and'distinct, the same being thrown outward into the tone arm; the sound box being of such a construction as to cooperate with the diaphragm to increase the volume of sound and to greatly amplify thesame. A further object of the invention to provide a diaphragm which is mounted in such a manner as to throw the sound waves directly into the sound box and which is re tarded against rebounding during the vibration of the diaphragm thus eliminating rattling and other noises.

Another object of the invention is to provide a diaphragm in which is mounted a concavo-convex cork member provided with an amplifying chamber disposed in direct line with the opening in the mouth of the tone arm so that the sound waves will be forced directly into the tone arm,

Another general object of the invention 1s to provide a sound box and dlaphragm of this character which is simple in construction, which consists of few parts, and which may be manufactured and sold at a low price.

With the above and other general objects and advantages in mind, the mvention con sists of the combinations of elements, constructions and arrangements, formations and operations and general assemblage, the details of which will be hereinafter enlarged upon and recited in the sub-joinedclaim,

On the drawings Figure 1 is a vertical sectional view taken through a sound box, embodying my improvements;

: Figure 2 is an elevation showing one face of the diaphragm; and

Figure 3 isan elevation showing the reverse face of the diaphragm;

Like character of reference designate like parts on all of the views.

Referring to the drawings in detail, the numeral 5 denotes the flared end of the sound box which is formed with a relatively thick end wall 6, the inner face of which is stepped as indicated at 7 to afiord annular circumferential recesses which radiate from the center of the wall 6, the periphery of the wall (3 being threaded and having engaged therewith an interiorly threaded collar 8 having an inturned flange 9.

My improved diaphragm consists of a vibratory disk 10 preferably of copper, and providedwith a comparatively large central opening 11. A cork disk 12 of relatively great diameter and having its outer face convexed and its inner face flat, is provided. The convex outer face of the disk 12 eliminates any tendency of the diaphragm to dampen the tone waves. Formed upon the flat face of the cork member 12 and centrally thereof is a concaved projection 13 which fits snugly in the diaphragm opening, the close contact of the cork and diaphragm forming a substantially unitary structure which eliminates burring sounds incident to the improper joining of two substances, so that a clear bell-like tone is produced. The concave face of said projection is disposed in direct line with the flared end of the sound box so that the sound waves will be collected therein and forced directly through the.

flared end of the sound box and into the tone arm producing a clear tone of rich volume.

A gasket 14 is interposed between the flange and disk and bears against the same at the outer edge thereof, this gasket being of polygonal cross section and positioned so that an apex contacts with the vibratory member. It will be thus seen that the vibratory disk will be free to vibrate and not be unduly held as would be the case if an ordinary gasket were positioned against this vibratory member.-

The stylus bar is indicated at 15 and is connected directly with the cork member and disposed centrally through the same a nut 16 being threaded upon this end of the stylus bar and accommodated in the concave face of the projection 13. It will be seen that the sound waves will be greatly amplified by providing the stepped recesses in the sound box and that the concaved face of the projection 13 will project the sound waves directly into the tone arm.

The construction illustrated and described is considered the preferred embodiment of the invention but it is to be understood that the same may be modified and altered in many respects and that my limits of such modification are governed only by What is claimed.

What is claimed is A diaphragm for phonographs having a comparatively large central opening with a cork disk mounted thereover and havin a flat face overlapping and closely contactln with one face of the diaphragm, said dlSK having its outer or exposed face convexed and provided on its inner face with a central projection seated snugly Within and extending through the opening in the diaphragm, the Wall of said opening being embedded in the perimeter of said projection whereby the diaphragm and disk form a substantially unitary structure, said projection having its inner face concaved to gather the sound waves and throw them out into the tone arm, and a stylus bar extending through the center of said disk and its projection.

In testimony that I claim the foregoing as my own, I have hereto affixed my signature in the presence of two Witnesses.

CHARLES CECIL BROSKIE.

Witnesses:

H. H. STALLARI). R. S. SALE, 

